Roxy Jacenko has hit back at critics after revealing she gets vitamin infusions.

On Tuesday, the 37-year-old shared social media a photo of herself attached to a vitamin IV drip.

"It was amazing," Roxy commented on the photo. "It's good for energy, liver cleanse and immunity. I went to @cosmoclinic."

The photo was quickly flooded with angry comments accusing her of promoting a potentially harmful health trend.

"It was amazing," Roxy captioned the photo. "It's good for energy, liver cleanse and immunity. I went to @cosmoclinic."

Vitamin infusions are supposed to combat the effects of fatigue and to boost the immune system by releasing a powerful cocktail of nutrients straight into the bloodstream. They are said to be useful for people recovering from illness or feeling run down.

But some of the PR queen's Instagram followers weren't convinced. One person told Roxy to "eat some fruit instead" while another said her post "sends the wrong message. Vitamins should come from food."

Others called it weird, and asked Roxy what was "the point in exercising if you won't eat the rights foods that give you vitamins?"

When somebody suggested Roxy was endorsing the procedure, she hit back.

Roxy responded with: "What I am doing is part of my monthly health plan – not a promotion".

Image: Instagram

"But you are influential as a celebrity," the commenter argued. "If you qualify it as helpful to you but lacking scientific basis then that's fine and I wish you the best with it, especially given how expensive it is."

According to the clinic Roxy went to, the treatments cost between $120 and $500.

The commenter continued: "In the post above you've made grand statements about it helping liver, immunity and energy. I haven't found any well conducted studies that back that up."

Many defended the Sydney-based publicist, suggesting she was using the treatment because of her history with cancer. Roxy did not confirm or deny this was the reason.

On Saturday, Roxy announced Oliver Curtis, her husband of five years, had proposed to her with the hopes of renewing their vows. She was spotted in the days following wearing a ring the 37-year-old gifted her, that is estimated to cost $450k.

The former investment banker was released from prison last month, after a serving a year for insider trading.